Practitioners - We Need to Talk! IBD in adolescents and young adults: are we paying enough attention?
This is a big topic and the blog post quickly got out of hand so I’ve broken it up into two parts to make it more “digestible” (yes pun intended!).
Part 1: The clinical landscape we can’t ignore
Recently, a 16-year-old boy came to see me with his mum, still wearing his footy shorts. He’d come straight from a hospital infusion. He should have been at training.
Instead, he was pale, flat, and trying very hard not to look embarrassed while his mum described weeks of diarrhoea, weight loss and the steroid mood swings that were “way worse than the bowel stuff.”
He just wanted to get back to mucking around with his mates.
A few months later it was a 14-year-old girl. Bright. Capable. Planning her life around toilet access. She’d stopped going to soccer because she couldn’t predict her bowels. She was on immunosuppressants. Ferritin scraping in. Vitamin D low. Anxiety so high.
Sadly, these are not rare cases anymore.
In Australia, more than 179,000 people are living with inflammatory bowel disease, and, gobsmakingly, peak onset sits between 15–29 years.¹ Globally, the burden continues to climb, with millions affected and rising incidence in newly industrialised countries.² ³ Australia is consistently described as a high-prevalence nation.⁴
We are seeing this in real time in our clinics, and honestly, I don’t think we are talking about it enough.
What’s also increasing in the background is the use of microbiome testing in this cohort. And with that, a new layer of confusion: we have more data than ever, but very little clarity on how to interpret it in young people with IBD.
The uncomfortable middle ground
Let me say this clearly: biologics and immunomodulators save lives. They reduce hospitalisations and surgery and many of our young patients need them.
But that is not the whole story.
IBD is increasingly understood as a disease shaped by gene–environment interaction. Genetics load the gun; environment pulls the trigger. Unfortunately, more and more frequently, early in life.
Large reviews consistently associate IBD risk with:
Urbanisation and industrialised environments⁵
Early-life antibiotic exposure⁶
Smoking (particularly for Crohn’s disease)⁷
Western dietary patterns and high ultra-processed food intake⁸
Vitamin D deficiency⁶
None of these are fringe concepts. Many of these factors intersect directly with the gut microbiome yet we rarely translate that into practical, clinical conversations with teens and their families.
So why are we not proactively discussing IBD risk when we speak about microbiome health in children? When we counsel teenagers on vaping? When we talk about food quality in families with autoimmune history?
I get it, it’s tricky. We don't want to be fear-based and dramatic. But can we have these conversations in a clinically grounded and kind way that builds connection rather than pushing patients away.
This isn’t about guilt
When a child develops IBD, parents often look for something to blame. Diet. Antibiotics. Stress. Themselves.
That is not helpful. It is also not accurate.
Risk is multifactorial. Many children exposed to these factors never develop IBD. Some develop it despite “perfect” lifestyles.
Our role is not to retrospectively assign cause. It is to thoughtfully reduce modifiable risk where possible and to recognise red flags early.
That distinction is so important.
Where we actually add value
If we are honest, prevention rarely looks dramatic. It looks like:
Supporting microbial resilience after antibiotic courses
Encouraging dietary diversity and fibre adequacy where tolerated
Reducing reliance on ultra-processed foods
Monitoring iron, vitamin D and growth in at-risk teens
Having straightforward conversations about smoking and vaping
Taking persistent bowel symptoms in young people seriously
It also looks like knowing when to refer.
Chronic abdominal pain plus weight loss, nocturnal symptoms, blood, growth faltering - that is not “just IBS.” Early referral changes outcomes. Delayed diagnosis increases complication risk.
It’s important to be both clinically comprehensive and appropriately cautious.
A rise in our young people
Peak onset in Australia sits in the 15–29 age range.¹ These are school years. Apprenticeships. First jobs. University. Sport. Social identity.
IBD ruthlessly interrupts that trajectory. Instead we see nutritional depletion, fatigue, anxiety and heartbreakingly, the grief of missing out.
As allied health clinicians, the gut and diet are central to our work, and we are well positioned to support:
Nutritional optimisation alongside medical therapy
Fatigue and micronutrient recovery
Gut-directed dietary strategies when appropriate
Stress regulation
Family education that is evidence-informed rather than internet-driven
But to do that well, we need to be informed and proactive, not reactive.
The wake-up call
IBD is not rare and it is not niche, it is no longer confined to tertiary hospitals. If our profession positions itself as leaders in microbiome health, chronic disease prevention and lifestyle medicine, then we cannot overlook a condition that sits directly at that intersection.
This does not require alarmist messaging. It requires us to:
Stay current with epidemiology
Understand established risk factors
Avoid overstating dietary causation
Collaborate with gastroenterologists
Communicate carefully with families
Most importantly, it requires us to speak about it calmly, competently and consistently.
Because those teenagers sitting in our rooms? They are not looking for ideology. They are looking for real help. And they deserve practitioners who understand the terrain they are navigating.
Where microbiome testing fits
One of the most common questions I’m seeing now is this:
“We’ve done a microbiome test… but what does it actually mean?”
In teens with IBD, this is not a simple question.
Reduced diversity. Shifts in key species. Functional changes in microbial activity, these patterns are real, but they are also easy to misinterpret without context. This is where I think we need to be more precise as a profession.
Not every abnormal result requires intervention.
Not every “imbalance” is clinically meaningful.
And not every recommendation improves outcomes.
If we’re going to use microbiome testing in this space, we need a clearer framework for interpreting what we’re actually seeing, particularly in adolescents, where growth, hormones and immune development are still in flux.
Thanks for reading!
Curious about how the microbiome connects to conditions like IBD? Join me for my free webinar on 26 May.
References
Crohn's & Colitis Australia. (2025). State of the Nation in IBD Report. https://crohnsandcolitis.org.au/advocacy/our-projects/ibd-state-of-the-nation/
GBD 2021 Inflammatory Bowel Disease Collaborators. (2024). Global burden of inflammatory bowel disease in 2021. Gastroenterology.https://academic.oup.com/gastro/article/doi/10.1093/gastro/goaf082/8253331
GBD 2019 Inflammatory Bowel Disease Collaborators. (2020). Global prevalence and burden of IBD. Lancet Gastroenterol Hepatol.https://pubmed.ncbi.nlm.nih.gov/36977543/
Kaplan, G.G. (2021). The global epidemiology of IBD. Nature Reviews Gastroenterology & Hepatology.
Soon, I.S. et al. (2012). Urban environment and IBD risk: a meta-analysis. BMC Gastroenterology.https://bmcgastroenterol.biomedcentral.com/articles/10.1186/1471-230X-12-51
Agrawal, M. et al. (2019). Environmental risk factors for IBD: umbrella review. Gastroenterology.https://www.sciencedirect.com/science/article/pii/S0016508519367095
MedicineInsight Study Group. (2021). Prevalence and risk factors of IBD in Australian general practice. BMJ Open.https://pmc.ncbi.nlm.nih.gov/articles/PMC8158877/
Ananthakrishnan, A.N. et al. (2016). Environmental and dietary risk factors in IBD. Inflammatory Bowel Diseases.https://pubmed.ncbi.nlm.nih.gov/27059169/
